The present invention relates to a speed reduction device and, more particularly, to a magnetic speed reduction device.
Speed reduction devices are interposed between a driving shaft and a driven shaft to produce a rotational speed of the driven shaft which is less than the rotational speed of the driving shaft. Speed reduction devices are used in a wide variety of applications, such as for example in conjunction with electric motors. A speed reduction device can be coupled between the motor shaft and a driven shaft to effect rotation of the driven shaft at a speed appropriate for a particular application. One type of speed reduction device comprises a gear train which is mechanically coupled between the shaft of the electric motor and the driven shaft.
The foregoing speed reduction devices all require a direct mechanical connection between the motor or engine turning the driving shaft and the driven shaft. In some applications, this moving mechanical connection may be disadvantageous. One such application where a moving mechanical connection is disadvantageous is in fluid or air systems under high pressure, and especially such systems wherein the rotational movement of the motor must be transmitted through a sealing barrier. Typically, a rotating shaft extends through the barrier and seals between the rotating shaft and the barrier prevent leakage. These seals may be subject to stress, and may wear out frequently.
An additional feature of many prior art speed reduction devices is that rotation of the driven shaft produces rotation of the driving shaft at an increased rotational velocity. Such reverse transmission of power may not be desirable in some speed reduction applications, however.
It is seen therefore that a need exists for a speed reduction device which does not require direct mechanical connection between the driving and driven shafts, and which does not affect rotation of the driven shaft in response to rotation of the drive shaft.